Cortical surface intracranial electrodes identify clinically relevant seizures missed on scalp EEG after traumatic intracranial hemorrhage.

Seizures and other electrophysiological disturbances are an under-recognized cause of coma, focal deficits, and prolonged encephalopathy following subdural hematoma evacuation. In these patients, it is possible that seizures remain unrecognized on scalp EEG. It has been shown that a high burden of seizures and other electrophysiological disturbances exist following surgical evacuation and underlie the encephalopathy commonly seen in this patient population, predisposing them to medical complications and confounding estimates of prognosis. As part of a research protocol, we are performing intraoperative placement of cortical surface (non-parenchyma penetrating) intracranial EEG on patients who present after trauma and require emergent decompressive hemicraniectomy. In this case report of a patient with high-velocity traumatic epidural, subdural, and subarachnoid hemorrhages, we identified frequent non-convulsive seizures or seizure-like SIRPIDs with intracranial cortical surface monitoring that were not identified on simultaneous scalp EEG. Stimulation consistently triggered these electrographic seizures in addition to rhythmic lateralized periodic discharges. His mental status improved rapidly after resolution of these electrographic seizures shortly after increasing antiseizure medications, suggesting that they may have been contributing to his encephalopathy. More research is needed to determine the frequency of this phenomenon and determine whether treatment of such seizures improves patient outcomes.